There’s a lot to love about the change from summer into autumn. Cooler walks, leaves underfoot and, for our dogs, a whole new collection of smells to investigate.

As late summer turns into autumn, there are a few new things worth keeping an eye out for on your dog walks. Fungi begin appearing in damp conditions, followed by fallen conkers and acorns as autumn gets underway.

Most will simply become part of the scenery. But if your dog is particularly curious — or has a habit of investigating the world with their mouth — it helps to know what should stay on the ground.

Here’s what to look out for, what can cause a problem and what to do if your dog gets there first.

Are conkers poisonous to dogs?

Yes. Conkers are the seeds of the horse chestnut tree and contain aesculin, a substance that can make dogs unwell if eaten.

The reassuring part is that serious cases of conker poisoning in dogs are considered uncommon. Conkers have a bitter taste, so many dogs won’t eat large amounts. Even so, chewing or eating them can cause digestive upset and other symptoms.

There’s another reason to keep them out of reach. Conkers are large, hard and conveniently ball-shaped, which means swallowing one whole could cause choking or a blockage in the digestive system.

They can be particularly tempting for dogs who love carrying things around. To them, a conker may look suspiciously like a very small tennis ball.

Signs that your dog may be unwell after eating conkers can include:

• Vomiting or diarrhoea
• Drooling
• Abdominal discomfort
• Loss of appetite
• Restlessness or lethargy
• Wobbliness or tremors in more serious cases

If you know or suspect your dog has eaten a conker, contact your vet for advice.

Can dogs eat acorns?

No. Acorns are another autumn find best left on the ground.

Acorns contain tannins, naturally occurring compounds that can make dogs unwell when eaten. They may cause vomiting, diarrhoea, abdominal discomfort and loss of appetite.

Serious cases are uncommon, but eating larger quantities can cause more significant problems. Their hard shape also means a swallowed acorn could potentially cause a blockage, particularly in a smaller dog.

Acorns begin maturing towards the end of summer and into autumn before falling from oak trees. Once they start to drop, there can suddenly be rather a lot of them — often tucked among fallen leaves where they’re much easier for your dog to find than for you to notice.

If your dog has eaten an acorn, particularly if you don’t know how many they’ve eaten, contact your vet for advice.

Are wild mushrooms poisonous to dogs?

Some can be.

Many wild mushrooms won’t cause serious harm, but some species of fungi can be highly poisonous to dogs. The difficult part is that telling one species from another isn’t always straightforward.

Warm, damp weather can encourage fungi to appear, which is why you may start noticing more mushrooms from late summer and through autumn.

The simplest approach is to stop your dog from eating any wild mushroom or fungus you find on a walk.

If they do manage to eat one, contact your vet promptly rather than trying to decide for yourself whether it’s a safe variety.

If possible, take clear photographs of the mushroom and where it was growing. This may help with identification and give your vet more information to work with.

There’s no reason to start avoiding woodland walks when mushrooms appear. Just keep a closer eye on dogs who are enthusiastic scavengers, particularly after wet weather.

What else should you look out for on autumn dog walks?

Conkers, acorns and mushrooms are some of the most recognisable changes underfoot, but there are a few other seasonal things worth knowing about.

Autumn crocus

Autumn crocus (Colchicum autumnale) flowers in late summer and autumn and can be highly toxic to dogs if eaten.

It’s more likely to be encountered in gardens and grassy areas than picked up like an acorn or conker, but it’s worth recognising if you have a dog who likes investigating plants.

Yew

Yew trees aren’t an autumn-only concern, but they’re worth knowing about. They’re commonly found in gardens, parks, hedges and churchyards, and parts of the tree can be highly toxic if eaten.

Don’t allow your dog to chew or eat yew foliage, seeds or berries.

Fallen fruit

Apples and other windfall fruit are another familiar sight as summer comes to an end.

Fresh apple flesh is safe for most dogs in moderation, but old fruit that’s been sitting on the ground is a different matter. Fallen fruit can begin to ferment as it rots, while stones, pips and large pieces can bring additional risks depending on the fruit.

If you have fruit trees at home, regularly clearing old windfalls is an easy way to remove the temptation.

Blue-green algae

Blue-green algae is more closely associated with warmer weather, but it’s still worth being aware of around lakes and ponds in late summer and early autumn.

Also known as cyanobacteria, some blooms can produce toxins that are extremely dangerous to dogs.

You can’t reliably tell whether a bloom is toxic simply by looking at it. Pay attention to local warning signs and keep your dog away from water with visible scum or unusual discolouration.

If you think your dog may have come into contact with blue-green algae, seek veterinary advice immediately.

What should I do if my dog eats something on a walk?

Dogs are quick. Sometimes they’ve swallowed whatever they’ve found before you’ve even worked out what it was.

If you think your dog has eaten something potentially harmful, try to establish what they ate, roughly how much and when it happened, then contact your vet for advice.

A few things can help:

Take a photo. If it’s a mushroom, plant or something you don’t recognise, photograph it and the area where you found it.

Keep any packaging. If your dog has eaten a household or garden product, keep the packaging so your vet can see exactly what it contains.

Don’t try to make your dog sick. Never induce vomiting at home unless a veterinary professional has specifically instructed you to do so.

Keep an eye on your dog. Vomiting, diarrhoea, excessive drooling, abdominal pain, loss of appetite, unusual tiredness, wobbliness, tremors or a noticeable change in behaviour all warrant veterinary advice.

And don’t feel you have to wait for symptoms before making the call. If you know your dog has eaten something potentially harmful, your vet can advise you on the best next step.

Making autumn dog walks a little easier

You don’t need to spend the whole season watching the pavement.

A reliable “leave it” and “drop” are two of the most useful things to practise with a dog who likes picking things up. It’s much easier to build those skills somewhere calm before testing them against a particularly fascinating acorn.

For dogs who love carrying things, bringing a favourite toy can give them something better to occupy their mouth.

If your dog is a determined scavenger, keeping them a little closer through areas covered in acorns, conkers or fungi can make walks easier too.

And don’t forget the garden. Clearing fallen fruit, conkers and acorns where possible and knowing which plants are growing within your dog’s reach can prevent a lot of opportunistic snacking.

Enjoying autumn together

Seeing conkers, acorns or mushrooms doesn’t make a walk dangerous. They’re normal parts of the changing landscape — they just aren’t things we want our dogs eating.

Knowing what to look out for means you can make a few sensible decisions when you need to, without worrying about every leaf or mushroom along the way.

Then you can get back to what autumn walks are really about: cooler air, muddy paws, plenty of sniffing and taking the long way home.